And, to be honest, I think there's benefit to being at arms-length with tenants. 

This may require increasing his income for a short time working extra and cutting back on non-essential lifestyle things or improvements to the property, which isn't his yet.

Is there a world where there are any benefits?

If you go to an experienced HML there will be an educational benefit to speaking to them about the property that could be better to have happened before you negotiate the contract.

So essentially I would be cash flowing the same, but will have 2 properties. 

For a more passive approach but still with potential tax benefits of long term ownership I would probably invest in an outstanding sponsor's syndication or NNN commercial leases.However, if the only capital I had was borrowed from my home, I would address that issue. 

After my last trip I have to admit the concerns outweigh the benefits and I am going to sell the boat up here and use the money as down payment on another rental.  

You may have some liability protection for assets not held in the LLC and check with an accountant for any possible benefits from the new tax law.

That is the primary benefit of a LLC 99.9% of the time ........  

@Upen Patel :  So, if I am reading into this correctly, there is no real benefit to being a co-borrower as opposed to a guarantor on the LLC loan.